Apparatus for testing the balance of connecting rods



Sept. 7,1926;' I 1,598,796

R. M. WILLIAMS APPARATUS FOR TESTING THE} BALANCE OF CONNECTING RODS Filed June 16, 1923 v Patented Sept. 7, 1926.

Ubll'i ttfs RALPH M. WILLIAM S, 0F DETROIT,

MICHIGAN, ASSIGNQR TO PACKARD MOTOR CAR COMPANY, OI. IGEI'ROIT, ltlflCl'rlilGAN, A CORPORATICN OF MICHIGAN.

APPARATUS FOR TESTING THE BALANCE OF CONNECTING RODS.

Application filed June 16, 1323.

This invention relates to internal combustion engines, particularly to the connecting rods thereof, and it has for an ob ect to provide a method and apparatus by which such connecting rods may be quickly and easily matched in sets for use in such engines.

Another object of the invention is to provide a single device by which connecting rods may be matched for characteristics of both weight and center of gravity.

Other objects and structural details of the invention will appear from the following description taken in connection with the drawings, which form a part of this specification, and in which:

Fig. 1 is a side elevation of a device embodying the invention;

Fig. 2 is an end elevation of the device shown in Fig. 1;

Fig. 3 is an enlarged detail section, substantially on the line 33 of Fig. 1, showing the connecting rod suspension means, and

Fig. 1 is a cross section through one of the suspension rings.

It is highly desirable in the construction and operation of internal combustion en gines to eliminate as much as possible the stresses and vibration caused by a lack of balance of the moving parts, a d with this end in view it has been the practice of manufacturers of such engines to balance the crank shafts thereof, and as far as practicable the connecting rods associated with the crankshafts. Such a condition of balance assumes that the connecting rods employed in any given engine have been substantially the same weight and that their centers of grav ity are located at substantially the same distance from the axes of their crank shaft bearings.

The average run of connecting rods manufactured by modern production methods are found, however, to vary considerably from any given standard, and various schemes have been proposed for matching up sets of such rods in which the individual rods of each set would have substantially the same weight and center of gravity characteristics.

Such procedure has heretofore involved the matching of succesisve rods against a master rod, or against one arbitrariiy select ed, until enough. rods were found within Serial No. 645,715.

the permissible percentage of variation from the rod selected to complete a set. Furthermore, the' apparatus used in the various weighing operations has frequently been of a character to seriously impair the sensitiveness of the operation, and this has been particularly true in the determination of the center of gravity characteristic.

By this invention is provided a method of quickly and accurately matching sets of connecting rods within any desired limits of permissible variation. It also provides apparatus adapted for the efficient and economical practice of the method.

Referring to the drawing, at 10 is indicated a base plate, to which is secured an ordinary platform scale 11, having the usual load receiving platform 12 adapted to operate indicating mechanism 13, including a graduated dial 14 and a pointer 15, as clearly shown in F 1. The indicating mechanism is preferably housed in a suitable cas ing 16.

gpaced from the platform 12 is a standard 17, rigidly attached to the base plate 10 in any convenient manner. Projecting from the upper end of the standard 17 is a transverse bracket memberltl, the upper side of which is provided with guide notches or grooves 19.

Secured to the platform 12 of the scale 11 is a similar standard 22 provided with a projecting bracket member 23, notched or grooved at 19 in a manner similar to the bracket member 18. The grooves in the bracket members 18 and 23 are adapted for cooperation with pairs of suspension rings 24 and 26, formed to provide inwardly disposed knife edges 25, which bear in the grooves on the bracket members. Suspended from the rings 24 and 26 are U-shaped arbors 27 and 28, the upper limbs of which rest on the knife edges 25. The lower limbs of the arbor-s 27 and 28 are adapted to support the small orv piston pin end 29, and the large or crank shaft end 31 of a connecting rod 32, respectively.

The dial 14 is preferably graduated into suitable units, such as ounces and fractions thereof, and may also be provided with suitable limit marks, indicating the permissible variation above and below the specified coni'iecting rod weight.

in the practice-of thi method, the work man both was total. weight and the Weight of the crank shaft. end of each connecting rodon the same devlce. A given connecting rod 32 1s taken from the manufactured stock to be tested and placed on crank shaft end of the oonnectin 7 rod,

which. is. an index of; the. position of the center of. gravity thereof; These readings are taken in. succession oneach of-therod-s constituting the stockto, be tested. If. des r e We ght; f e Y ank; s af d. of the. rod. may bedstermined before thetotal weight thereof.

As. fast as these.- readings are taken, the successive rods are placed in; groups in; any convenient place, such, as. suitable bins, according to the respective readings. ofthe pointer 16, Thusfeach such groupwill contain only rods which have substantiallythe same weight. and center of gravity character,- istics, hen; any groupcontains anumber of rods equal to the number of cylinders inlthe engine for which they are being mannfactured, the set is complete, and the rods may be removed for installation. For exa1nple,in the nanufacturecf a;fonr cylinder in ny iv roup weu d c n a n a complete set when there were four rods therein.

It willv beobvious thatthe methodof; support, of the connecting. rods. 32 on the arbors 2'7 and 28, which in turn depend; from the knife edges 25. of, the rings. 24 and. 26, insures that therod. is allowed to freely assuine, its natural position of, suspension, so that errors. in, thescale reading due to constraint of, therod are negligible. 7

It will also be seen that this. invention provides .a method by which sets of: connecting rods. may be very rapidly assembled, Itfisnot necessary to match any giveirrod against, any other rod, or, against anystandard data, as long as it comes within the limits specified, which is determined simultaneously with the weight. The operator simply Weighs up the rods as rapidly as he can place them on the device, removes them and puts them in their proper groups.

It will be understood, that various forms of the invention other than those described above may be used without departing from the spirit or scope of the invention.

hatis claimed is:

1;. The combination v in a device for determining the weight data of connecting rods of internal, combustion engines, of a base plate, a platform scale thereon, stand ar-ds.secured to the platform and to the base plate, arbors adapted to cooperate with, the ends. of the. connecting rod, and means ineluding; knife edges adapted. to suspend the a o s. rom tan a ds- 2. Thecombination ina device for, we'iglr ing connecting ro ds, of a platform scale mounted on a base plate, standards. secured to,the.plat;form and tothe base platerespectiyely, brackets projecting from the stand,- ards, rings suspended from the bracketsand provided with. knife edges, and i-shaped mandrels adapted to support the connecting rod,and carried by said knife edges.

8. The combination in a device for eigh.- ing. the, connecting rods of internal combustion engines, of a. scale, a standard; sup ported thereon, a stationary standard in spaced relation thereto, U-shaped arbors each having a leg; adapted for cooperation With the ends of a connecting rod and means for freely suspending. said arbor-s from the standards.

e. The combination in a; device fon weighing; connecting rods of a base plate, a platform secured thereon, a standard secured to the platehaving a projecting arm, a standard on thebase plate spaced from-said platform standard; and having a similar ar n, arbors adapted toco-operate with the ends ofthe connecting rod, and members having knife edgesto freely suspend the arbors and connectingrod from said arms.

In testimony whereof I affix my si nature.

R H: WI-nnriiMs. 

